A STRATEGY FOR FITTING PARTIALLY BLENDED RIDGES IN GONG SOLAR P-MODE SPECTRA

Observations of solar oscillations by the Global Oscillation Network G roup (GONG) using a network of telescopes deployed around the Earth el iminate temporal aliases from the oscillation power spectra to a very substantial extent., making the measurement of oscillation mode parame ters much cleaner than with single-site observations. However, the pro blem of spatial aliasing, which arises from the fact that we see only one side of the Sun, still causes some problems. We discuss some of th e issues affecting the estimation of medium-l solar acoustic mode para meters from the data obtained by the GONG network. and in particular t he contamination by spatial leakage. We determine the areas in the l-n u plane in which such leakage is a problem, and finally we describe a method for improving the mode frequency estimation in such regions, th us extending the range of modes for which useful frequency estimates c an be obtained.